Environmental DNA, also known as eDNA, from the carp was discovered in Sandusky Bay this summer during a study by the U.S. Fish and Wildlife Service. No live carp have been found.
"We recognize that this is an indication of the presence of eDNA in the water," said Rich Carter, who heads fish management and research for the Ohio Department of Natural Resources. "There is an uncertainty about the source of that eDNA. The potential sources could include live fish or some other source that we don't know at this point."
The carp got into the Mississippi River system as fugitives from fish farms. Scientists fear if they get into Lake Michigan from the Chicago River they would spread throughout the Great Lakes and out-compete native species because of their feeding habits and reproductive capacity.
That could mean the end of important commercial and sports fisheries.
2014: The Year in Fashion [PHOTOS]
Man wanted for abduction of missing UVA student